Names and Formulas for Binary Acids

Binary acids are named by writing hydro followed by the root of the name of the halogen, then -ic,
and finally acid:

hydro(root)ic acid

The only exception to remember is that the “o” in hydro is left off for HI(aq), so its name is hydriodic acid
(an acid used to make pharmaceuticals).

Most chemists refer to pure HCl gas as hydrogen chloride, but when HCl gas is dissolved in water, HCl(aq),
the solution is called hydrochloric acid. We will follow the same rule in this
text, calling HCl or HCl(g) hydrogen chloride and calling HCl(aq) hydrochloric
acid. The same pattern holds for the other binary acids as well.

You will be
expected to be able to write formulas and names for the binary acids found
below . Remember that it is a good habit to write (aq)
after the formula.

HF(aq) - hydrofluoric acid

HCl(aq) - hydrochloric acid

HBr(aq) - hydrobromic acid

HI(aq) - hydriodic acid

H2S(aq) - hydrosulfuric acid

HF - hydrogen fluoride or hydrogen monofluoride

HCl - hydrogen chloride or
hydrogen monochloride

HBr - hydrogen bromide or
hydrogen monobromide

HI - hydrogen iodide or hydrogen moniodide

H2S - hydrogen sulfide or dihydrogen monosulfide

Names and Formulas for Oxyacids

To name oxyacids, you must
first be able to recognize them by the general formula HaXbOc,
with X representing an element other than hydrogen or oxygen. It will also be
useful for you to know the names of the polyatomic oxyanions, because many
oxyacid names are derived from them. If enough H+ ions are added to a
(root)ate polyatomic ion to completely neutralize its charge, the (root)ic acid
is formed
(See below. ).

If one H+ ion is
added to nitrate, NO3-,
nitric acid, HNO3,is formed.

If two H+ ions
are added to sulfate, SO42-,
sulfuric acid, H2SO4,
is formed.

If three H+ ions
are added to phosphate, PO43-,
phosphoric acid, H3PO4,
is formed.

Notice that the
whole name for sulfur, not just the root, sulf‑, is found in the name
sulfuric acid. Similarly, although the usual root for phosphorus is phosph-,
the root phosphor‑ is used for phosphorus-containing oxyacids, as in the
name phosphoric acid.